1. Field of the Invention
The present invention relates to conveyors and, more particularly, to a conveyor or walking floor system for use in transferring items resting upon the conveyor or walking floor system and, most particularly, to a conveyor or walking floor system installed on the floor of a cargo transport vehicle or container, the conveyor or walking floor system providing automated transfer of items into and out of the cargo transport vehicle or container.
2. Background Information
Conveyor or walking floor systems are well-known devices used in the trucking industry for automated movement of containers and the like into and out of a cargo transport vehicle, such as a semi-trailer. Many patents have been granted that concern rail conveyor-walking floor systems for moving containers or bulk solids in a selected direction. Examples of such patent are detailed below.
Peterson, in U.S. Pat. No. 2,629,504, describes an improved unloading mechanism for a vehicle, having a reciprocating bottom for discharging a load. The reciprocating bottom consists of a plurality of longitudinally extending bottom portions constructed to reciprocate and transverse contiguously positioned longitudinal portions, which are movable successively in a longitudinal direction, with the portions being movable in concert in an opposite direction for unloading a vehicle. The load carrying bottom includes of a plurality of first and second floor portions positioned in transverse contiguous relation. The first and second portions are alternately positioned, and alternate portions are movable successively in a forward direction, independently of a load carried on the bottom. All the portions are movable rearwardly as a unitary structure for moving a load to the rear of the vehicle and for discharging the load.
In U.S. Pat. No. 2,973,856, Brooks discloses a conveyor for use in trucks and trailers, loading platforms and the like, which is capable of transporting heavy loads. The conveyor requires a minimum sacrifice of headroom when used in a truck body or the like, on the order of 2″. The conveyor members extend the entire length (or width) of the truck bed or the like, to engage the entire load simultaneously and evenly, and the members move through a short cyclical path in effecting step-by-step advancement of the load in either direction. The invention provides a novel conveyor control system having a pair of alternatively operable conveyor elements moving between limit positions, where the arrival at a limit position is employed for rapid and automatic recycling. The conveyor members and base include opposed triangular ramps with rollers there between to effect raising and lowering of the conveyor members. Alternatively, rocking cams (202), which raise and lower the conveyor elements, are provided.
La Belle in U.S. Pat. No. 3,225,905, describes a reciprocating conveyor in which a series of spaced elongated stationary members, permanently mounted on the base, are reduced in cross section on the forward end to provide a vertical shoulder having a socket. An upright plate on the end of each stationary member has a hole, longitudinally aligned with the socket in the vertical shoulder. A longitudinally disposed roller, provided with end pintles, is mounted for rotation on the forward portion of each elongated stationary member. The end pintles on the rollers are supported in the sockets and the holes in the upright plates so that the upper periphery thereon coincides with the plane of the top surface on the elongated stationary members. A coupling strap, having a pair of spaced openings, is connected adjacent the end of each outer elongated stationary member by means of a bolt.
A pair of transverse shafts is rotatably supported in the bearings mounted in the elongated stationary members. Elongated movable members, disposed between the spaced elongated stationary members, are reduced in cross section on each end. A tubular bearing is mounted adjacent the rear end of each elongated movable member, and a downwardly disposed flat bearing is provided on the forward end of each member. Spaced cams, disposed in the tubular bearings, are mounted on each of the transverse shafts, intermediate the stationary members, and removably secured thereon by means of keys. The cams on the transverse shaft are in sliding engagement with the downwardly disposed flat bearings on the elongated movable members. A reversible electric motor is detachably connected to one of the transverse shafts by means of a coupling. A sprocket is mounted on each of the transverse shafts and connected together by means of an endless link chain.
In operation, the electric motor, when energized, drives the transverse shaft, which transmits the driving effort through the link chain to the other transverse shaft. As the transverse shafts are rotated, they drive their respective cams in a clockwise or counterclockwise direction depending upon the direction in which the electric motor is rotating. A clockwise rotation of the cams elevates the elongated movable members above the upper surface of the stationary members to the broken line position, shown in FIG. 2. Simultaneously, rotation of the cams on the transverse shafts also shifts the elongated movable members in a forward direction relative to the stationary members. Any load on the conveyor is thus moved toward the rollers on the elongated stationary members, a fixed distance upon every complete revolution of the cams. When the load has thus been shifted so that it is being supported entirely on the rollers, it can be readily removed from the conveyor by application of a transverse force of sufficient magnitude. A load can likewise be conveniently placed on the conveyor by means of the rollers. A counterclockwise rotation of the cams moves the load toward the rear of the conveyor in the manner previously described.
In U.S. Pat. No. 3,534,875, Hallstrom, Jr. discloses a reciprocating conveyor that includes a plurality of groups of at least three elongated slats, arranged side by side to form a conveyor type truck bed. The slats of each group are connected to a drive mechanism in such manner that there are always a greater number of slats of each group moving simultaneously in the conveying direction, while the remaining slat or slats of the group move in the opposite direction. The drive mechanism includes rotary, eccentric, drive cams and drive rods to power the conveyor. Power is provided to the rotary, eccentric, drive cams through a universal joint connected to the drive shaft of the conveyance.
Hallstrom, in U.S. Pat. No. 4,143,760, describes a conveyor, having at least one group of at least three elongated slats mounted side-by-side on a frame for longitudinal reciprocation to form the conveyor. The slats are connected to a fluid pressure drive mechanism, which is operable to move all of the slats of each group from a start position, simultaneously, in a load-conveying direction and then to move the slats of each group, sequentially, in the opposite direction from the advanced position back to the start position. The slats of each group are interengaged releasably in the conveying direction to insure simultaneous movement.
In U.S. Pat. No. 4,508,211, Foster discloses generally horizontally disposed, bracing trusses, interconnected between the bottoms of the longitudinal drive beams and the bottoms of the associated transverse drive beams, within a reciprocating floor conveyor. Trucks equipped with reciprocating floor conveyors are backed into a receiving house, and the conveyors are used for unloading bulk material from the trucks into the receiving house. The bulk material is conveyed from the receiving house up to an elevated inlet at one end of an elongated enclosure. The enclosure includes a reciprocating floor conveyor at its bottom and an elevated screw conveyor at its top. The reciprocating conveyor is operated to move bulk material out from the enclosure at a controlled rate. The elevated screw conveyor is used for rapidly distributing additional bulk material that is being added at the elevated inlet and the trailing portion of a previous deposit of the bulk material, which has been moved away from the elevated inlet by the reciprocating floor conveyor.
Gist, in U.S. Pat. No. 5,560,472, describes a walking floor having a plurality of floor beams to support a load, and being longitudinally reciprocal to move the load longitudinally to an unloaded condition. The floor beams are supported by a transverse subfloor, having guides to control movement of the floor beams, and bearing/seal devices mounted to the subfloor and in bearing and sealing contact with the floor beams to prevent material that is part of the load supported by the floor beams from migrating below the floor beams.
In U.S. Pat. No. 5,806,660, Foster discloses alternate conveyor slats, having laterally outwardly projecting, upper side portions, each with a depending, longitudinal, load transmitting bead. The beads sit down on and slide longitudinally along bearing/seal surfaces that are a part of upper side portions of the intermediate conveyor slats. The alternate conveyor slats are guided by longitudinal guide beams. Hold down members, secured to the guide beams, serve to resist unwanted upward movement of the conveyor slats. The intermediate conveyor slats are snap-fitted onto bearings, which, in turn, are snap-fitted onto longitudinal guide and support beams. The weight of conveyor slats, and the weight of any load on the conveyor slats, is transmitted by the contact of the bead with the bearing/seal surfaces to the conveyor slats. This weight, the weight of the conveyor slats and the weight of any load on conveyor slats, is transmitted to the bearings and from the bearings to the guide and support beams.
Quaeck, in U.S. Pat. No. 6,257,396, describes a load supporting and moving surface of a conveyor made up of longitudinal members called slats. The slats are edge to edge with small gaps between the edges. The slats are supported on longitudinal bearing strips, one edge of each slat on one strip, the other on an adjacent strip. The bearing strips are supported on longitudinal beams, evenly spaced and running lengthwise of the cargo space of the conveyance in which the conveyor is mounted. The longitudinal beams are supported by, and fastened individually to, crossbeams of the conveyance. The bearing strips slide longitudinally onto the longitudinal beams and the slats slide longitudinally onto the bearing strips. Clearance is provided for fastening the longitudinal beams from above. The upper surfaces of the bearing strips have longitudinal grooves in the center of their upper surfaces. Flanged ribs on their lower surfaces engage the flanges of the longitudinal beams to hold the strips in place. The edges of the slats are over the grooves. Flanged ribs on the bottom surfaces of the slats engage the flanges on the longitudinal beams or, in some configurations, the edges of the bearing strips. The conveyor includes hydraulic/mechanical apparatus well known in the art for reciprocating the slats in prescribed ways to move loads along the conveyor.
In U.S. Pat. No. 6,513,648, Halstrom et al. disclose a container of a mobile cargo trailer with a reciprocating slat type conveyor floor. The elongated slats are supported at their lateral edges on V-shaped bearings, which are mounted on Y-shaped supports integral with sub-deck sections on the container bottom and joined together with watertight seals. Three cross beams are connected to different groups of the slats and are coupled to hydraulic cylinders located outwardly of the front end of the container and in horizontal alignment with the slats. The cylinders are coupled to a hydraulic fluid pressure source through an arrangement of control valves to effect movement of the group of slats simultaneously in a load moving direction and, sequentially, in the opposite, slat-retracting direction, with interengaging abutments on the cross drives arranged for moving one of the cross drives and its slats by hydraulic power, applied only to the other two cross drive cylinders.
Wilkens et al., in U.S. Pat. No. 7,152,729, describe a reciprocating floor conveyor that includes floor slats and slide bearings. The floor slats include a top section, first and second side walls that extend downward from the top section, a first bottom flange integral with the first side wall and a second bottom flange integral with a second side wall. A top section cantilever portion extends laterally outward from the second side wall. A seal flange is integral with the first side wall and includes a seal support surface and a seal flange wall that cooperate with the first side wall to form a seal retainer channel position below the cantilever portion of an adjacent floor slat. The slide bearings have a cross beam, and right and left walls. Wings extend laterally outward from the top of the walls and sit on guide beams.
In U.S. Pat. No. 7,604,109, Foster et al. disclose a trailer and a dock with substantially identical slat conveyors. Each conveyor has alternating conveyor slats and lifting/holding slats. The trailer is backed up to the dock. Upper portions of the lifting/holding slats are coupled together at their ends. The confronting ends of the conveying slats are also coupled together. A mechanism, carried by the dock, raises and lowers the upper portions of the two sets of lifting/holding slats, and a drive mechanism, carried by the dock, reciprocates both sets of conveying slats.
Applicant has devised a rail conveyor system that overcomes many of the short comings of presently known transport system.